The death toll rose to 27 and 32 others were wounded when two female suicide bombers blew themselves up at an Iraqi police academy in eastern Baghdad on Tuesday, the US military said.

Two women wearing explosive vests blew themselves up in a classroom filled with police students at the police academy at about 12:45 a.m. (0945 GMT), the US military said in a statement.

Earlier, an Interior Ministry source said ten policemen were killed and 18 others wounded in two explosions in the academy near the ministry in central Baghdad.

"Two blasts rocked the police academy and killed ten people and wounded 18 others, all policemen," the source said.

The attacks came as Iraq's former president Saddam Hussein and his seven top aides went on trials for the fourth time on charges of crimes against humanity in the heavily fortified Green Zone in central Baghdad.